I read a scholarly article on oxidisation and collagen structure in the dermis and they mentioned the use of Retinoids topically. so I looked into retinoids (admittedly on Wikipedia) for an overview (Vitamin A and Retinoic acid, retinol etc) in the possible use on anti-ageing, which happened to state that carotenes are apparently "metabolized to β-ionone, and thus have vitamin A activity because they can be converted by plant-eating animals to retinol and retinal. Carotenoids that do not contain the β-ionone moiety cannot be converted to retinol, and thus have no vitamin A activity."
I cannot find anywhere by googling this, and as I am an amateur perfumer, not a chemist, with a genuine curiosity for an innocuous bottle of Beta Ionone that I use for fragrancing. I would be really grateful if someone could point out in layman's terms what is meant by "vitamin A activity" and could explain-
If using Beta Ionone on the skin it can possess the same qualities of the retinoids that are sold as anti-ageing products?
P.S I realise that beta-ionone is a possible cause for irritation on skin in certain amounts so this is not the question of safe amounts, it is the reaction in terms of the aforementioned that I am interested in.